Sodium barium aluminate and process of making the same



Patented Dec. 25, 1934 UNITE o .sTATE-s g meant SODIUM BARIUM AILUIVHNATE AND -OF-MAK'I'NG} THE SAME PROCESS 7 Elbert Fisher, I St. magi Mm, .aSsigiibr to National Pigments and Chemical Company, St

Louis, Mo, a corporation of Missouri Drawing. ApplicaticnMay 13,1931, Serial No.537;201 1 roiainis. (o rte- 52 This invention relates generally to a compound of barium and a process by which such a compound may be produced. The invention relates particularly to the production of a compound 5 comprising the oxides of sodium, barium and til aluminum or any solublebarium salt, and a processtof producing the same from insoluble barium sa s.

An object of'thisinvention, generallystated, is to provide a soluble barium salt.

Another. object of this invention is to provide a process for making :a soluble salt from an insoluble barium salt.

,Another object of this invention is to provide a process formaking' sodium barium aluminate;

A further object of thisinvention is toprovide a barium compound from which barium hydrate or barium oxide may be readily obtained.

A further object ofthis invention is to provide a barium'salt containing sodium and aluminum which maybe used in its original state in all processes in which barium oxide or barium hydrate have heretofore beenused and under circumstances in which it is desirable to add a-small quantity; of sodium and aluminum, such as in glazing processes in the ceramic industry. Other objects will become apparent to those skilled in theart when the following description isread: In accordance with this invention, a soluble barium salt, such as, for instance, one including the oxides of barium, sodium and aluminum, is produced from insoluble barium salt and a suitable salt of sodium with the addition of some alumina. This mixture is preferably heated to a sufiicient temperature either with or without a reducing agent to drive off the acidic content of I the barium and sodium salts and thereby produce a compound which is a true mixture of sodium aluminate and tri-barium aluminate. After such a roasting process has been concluded and all the acidic content driven oif, a soluble barium salt sodium barium aluminate (3BaO-Alz0a) (NazO-AlzOa) will remain.

The roasting process in which the acidic content of the barium and sodium salts is driven ofi may be conveniently carried out in any suitable type furnace, such as, for instance, the wellknown long brick-lined rotary type furnace or any other type which is suitable for withstanding high temperatures, such as for instance, l300- to 1500" C. The specificdimensions of the furnace are, of course, optional, but when it is desired to produce the compound by continuous operation and when a substantially large output is desired, a'furna'ce approximating feet has been found-preferable, With theme of such a furnace, the time required for converting a batch of the sodium-and barium salts with alumina into sodium barium aluminate in accordance with this invention-is generally from-three to four hours. It is-to be understood that theroasting process can'b'e carried out with any type of fuel, such as, for instance, with gas, coal oroil, and it is preferable'underall circumstances to maintain the flamev of the reducing character. Under some conditions of. operatiohQit is preferablealso to employ areducingagent, such as, for instance, coke or powdered coal, but under ordinary operation, the process may. be'satisfactorily carried out without thepresenceof such a reducing agent.

As an illustrativeembodiment of the process for producing .a soluble salt, such'as, for. instance, sodium barium aluminate, an'insoluble barium salt, such as, for instance, barium sulphate, which may be in the form of baryte ore, is preferably ground to a fineness of not less than 100 mesh. Similarly, a quantityof anysuitable sodium salt, such as,.for instance, sodiumichloride is ground tothe desired fineness. Likewise, a quantity ofv alumina is ground to the desired fineness and the three materials, alumina (A1203), barium sulphate (BaSO4) and sodium chloride (NaCl) are mixed together in molecular proportions and; the mixture then heated, in thefu'rnace as set forth above: Under most circumstances it is preferable to' add'a' trace of carbon for expediting the reaction. During the time in which the various materials are being roasted in the furnace, the sodium chloride is broken down by virtue of the presence of carbon monoxide and the chlorine is liberated so that the sodium is oxidized and remains as sodium oxide. The sodium oxide, however, is immediately broken down, the sodium replacing barium in the barium sulphate present so that a mixture of sodium sulphate and barium oxide is now present in the furnace. As the heating is continued, the sodium sulphate, by virtue of the carbon present, will be broken down into sodium sulphide, sodium oxide and sulphur dioxide, but since the sodium sulphide is unstable,

the sulphur thereof will readily be replaced by oxygen and the sulphur liberated as either the dioxide or trioxide.

impurities which may be present in the raw ma- It is apparent, therefore, that the gases which are liberated durterial, such as baryte ore. When the liberation of gases or acidic radicals has been completed, the material remaining in the furnace in the form of a clinker is a complex salt, comprising, barium oxide, sodium oxide and alumina. It has not beendefinitely determined whether or not the alumina undergoes any chemical change or action during the sintering process, but it is apparent that the resultant complex salt is a mixture of tribarium aluminate (3BaO-AlzO3) and sodium aluminate (NazO-AlzOa).

It is important that the temperature of the furnace be accurately controlled during the sintering process since it has been discovered that the barium content of the soluble salt is rendered, to an extent, insoluble, if the material is subjected to high temperatures for a substantial period of time. It is diflicult to pre-determine the proper temperature for production of high solubility barium content, and it is necessary to determine the proper temperature more or lessby experience. It may be pointed out, however, that the proper temperature for production of high solubility barium content is dependent to a great extent upon the portion of sodium salt present. For instance, it has been discovered that if the percentage of sodium chloride present be increased by 10%, the criterion temperature for production of high solubility barium content is reduced from 50 C. to C. It may be pointed out that the process in this invention is adaptable to the production of such a complex salt as has been hereinbefore described with the use of barium carbonate or witherite ore as a raw material. Moreover sodium carbonate may be used in lieu of the sodium chloride with more or less equal results. With the use of witherite ore as a raw material and the use of sodium carbonate, it may be pointed out, however, that different temperature conditions and longer periods of roasting are often necessary.

From the foregoing description it is apparent that a process has been described for producing a soluble barium salt, such as, sodium barium aluminate, from insoluble barium salt, such as, barium sulphate or barium carbonate, which may be continuously employed in a single furnace operation for the production of the soluble barium salt, which may beemployed in commerce either in solution or in the dry phase.

It is apparent that the process hereinbefore described and the resultant compound are susceptible of many modifications without departing from the spirit of this invention. Accordingly, it is to be distinctly understood that the foregoing description and the various terms employed therein set forth merely one illustrative embodiment, and it is apparent that many individual features are of utility without reference to other features, so that it is to be distinctly understood that such modifications and the use of such features as do not depart from the spirit of this invention, are, although not specifically described herein, contemplated by and within the scope of the appended claims.

Having thus, described the invention, what is claimed is:--

1. In the art of making soluble barium compounds, the process comprising, mixing barium sulphate, sodium carbonate, and alumina, and heating the mixture to a temperature suiiicient to drive off the acid radical of the barium salt.

2. 'In the art of making soluble barium compounds, the process comprising, mixing barium carbonate and sodium carbonate and alumina, and heating the mixture to a temperature suflicient to drive off the acid radical of the barium salt.

v 3. In the art of making soluble barium compounds, the process comprising, mixing barium sulphate and sodium chloride and alumina, and heating the mixture to a temperature sufficient to drive off the acid radical of the barium salt.

4.'In the art of making soluble barium compounds, the process comprising, mixing barium carbonate and sodium chloride and alumina, and heating the mixture to a temperature sufficient to drive off the acid radical of the barium salt.

5. A composition which has been fused comprising, tribarium aluminate and sodium aluminate.

6. A composition which has been fused comprising, a barium aluminate and sodium aluminate in intimate association resulting from concurrent production.

7. In the art of making soluble barium compounds, the process comprising, mixing a barium salt with a sodium salt, and alumina substantially in molecular proportions such as to yield a product having the formula (3BaO-Al2O3) and a product having the formula (Na2O-A12Os), and heating the mixture to expel the acid radicals from the salts and concurrently produce said products in intimate mixture.

ELBERT E. FISHER. 

